1. Technical Field
The present invention relates to a nonvolatile memory device, and more particularly, to a phase-change random access memory (PCRAM) device and a method of manufacturing the same.
2. Related Art
PCRAM devices apply joule heat to a phase-change material through a heating electrode serving as a heater, thereby causing the phase-change material to be phase-changed. The PCRAM devices store/erase data using an electrical resistance difference between a crystalline state and an amorphous state of the phase-change material.
A source for supplying heat to the phase-change material is current, and an amount of heat supplied depends on the amount and supply time of the current. The phase-change material has different resistances according to the crystalline state and the amorphous state of the phase-change material, and thus, logic information of the phase-change material is determined by the resistance.
Such a phase-change material may be in partial contact with the heating electrode so that the phase-change material is electrically coupled to the heating electrode.
However, crystalline uniformity in a phase-change material is degraded by a subsequent thermal process, and thus, the degradation of the phase-change material may cause the reliability of an operation between the phase-change material and the heating electrode to be degraded.
When complete separation between the phase-change material and the heating electrode is not obtained, the PCRAM devices are vulnerable to thermal disturbance.